Type 2 Diabetes Mellitus with Plantar Malignant Melanoma: Report of Two Cases and Literature Review

Abstract Background: Malignant melanoma is a highly malignant tumour that originates from melanocytes. Its prognosis is poor and motality rate is high. Malignant melanoma usually occurs in the skin, also known as cutaneous melanoma,but rarely in the foot. Case report: Here we report two cases of type 2 diabetes diagnosed as malignant melanoma of the foot and provides a review of literature. The first patient was a 70-year-old woman with a 7 year history of diabetes, who had a ulcer in the right heel for half a year. The second case, which occurred in a 66-year-old woman whose third toe of the right foot had been red, swollen and blackened for 2 months. Both of them had been treated as diabetic foot at first , and then been diagnosed of malignant melanoma by a pathological biopsy of the lesions. Conclusion: From two rare cases of plantar malignant melanoma,we suggest that clinicians should be alert to the occurrence of acral malignant melanoma in diabetic foot patients. When diabetic foot ulcers occur repeatedly and continue not to heal, and the pathological features of the lesions are similar to malignant melanoma, a pathological biopsy of the lesions should be performed promptly to obtain a clear diagnosis, avoid a missed diagnosis and improve the survival rate.